3121 rule used in training for muscle growth by body builders and fitness athletes :

This is a training principle that is incorporated by every professional bodybuilder and fitness athlete in his workout routine and if followed properly will give you results never seen as ever before.

3121 rule is a basic training rule which says that while doing your set, for each rep take about 3 seconds to perform the rep to reach one extreme, then 1 second rest and then take 2 seconds to revert back to normal position from where you started and then again 1 second rest and go on and on for each rep.

Try to apply this rule in all your exercises irrespective of which muscle is it or which ever exercise it might be, you will see the results yourself and never seen growth and pump in the muscle. This is a very common mistake done my most of new starters. While applying this technique into your routine take about 40 seconds of rest after each set and impose this rule in every repetition of each set. If you follow and impose this training principal properly into your routine, be ready to see never seen results in your body after workout